Genetic research into dyslexia
The genetic research into dyslexia has its roots in the work of Galaburda and Kemper, 1979,[1] and Galaburda et al. 1985,[2] from the examination of post-autopsy brains of people with dyslexia. When they observed anatomical differences in the language center in a dyslexic brain, they showed microscopic cortical malformations known as ectopias and more rarely vascular micro-malformations, and in some instances these cortical malformations appeared as a microgyrus. These studies and those of Cohen et al. 1989[3] suggested abnormal cortical development which was presumed to occur before or during the sixth month of foetal brain development.[4]
[edit] Genes and chromosomes associated with dyslexia
Molecular studies have linked several forms of dyslexia to genetic markers.[5] Several candidate genes have been identified, including at the two regions first related to dyslexia: ROBO1[6] on chromosome 3, DCDC2[6][7] and KIAA0319,[6][8] on chromosome 6[9] and DYX1C1[6] on chromosome 15.
A 2007 review reported that no specific cognitive processes are known to be influenced by the proposed susceptibility genes. Some studies have already started to include neurophysiological (e.g., event-related potential) and imaging (e.g., functional MRI) procedures in their phenotype characterisation of patients. Such samples are an important prerequisite for the identification of those processes that are most proximal to the effects of particular genes and their associated biological pathways.[10]
[edit] References
- ^ Galaburda AM, Kemper TL (August 1979). "Cytoarchitectonic abnormalities in developmental dyslexia: a case study". Annals of Neurology 6 (2): 94–100. doi:10.1002/ana.410060203. PMID 496415.
- ^ Galaburda AM, Sherman GF, Rosen GD, Aboitiz F, Geschwind N (August 1985). "Developmental dyslexia: four consecutive patients with cortical anomalies". Annals of Neurology 18 (2): 222–33. doi:10.1002/ana.410180210. PMID 4037763.
- ^ Cohen M, Campbell R, Yaghmai F (June 1989). "Neuropathological abnormalities in developmental dysphasia". Annals of Neurology 25 (6): 567–70. doi:10.1002/ana.410250607. PMID 2472772.
- ^ Habib M (December 2000). "The neurological basis of developmental dyslexia: an overview and working hypothesis". Brain 123 (Pt 12): 2373–99. doi:10.1093/brain/123.12.2373. PMID 11099442.
- ^ Grigorenko EL, Wood FB, Meyer MS, et al. (January 1997). "Susceptibility loci for distinct components of developmental dyslexia on chromosomes 6 and 15". American Journal of Human Genetics 60 (1): 27–39. PMC 1712535. PMID 8981944. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1712535.
- ^ a b c d Paracchini S, Scerri T, Monaco AP (2007). "The genetic lexicon of dyslexia". Annu Rev Genomics Hum Genet 8: 57–79. doi:10.1146/annurev.genom.8.080706.092312. PMID 17444811. http://arjournals.annualreviews.org/doi/abs/10.1146/annurev.genom.8.080706.092312?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%3dncbi.nlm.nih.gov.
- ^ Meng H, Smith SD, Hager K, et al. (November 2005). "DCDC2 is associated with reading disability and modulates neuronal development in the brain". Proceedings of the National Academy of Sciences of the United States of America 102 (47): 17053–8. doi:10.1073/pnas.0508591102. PMC 1278934. PMID 16278297. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1278934.
- ^ Paracchini S, Steer CD, Buckingham LL, et al. (December 2008). "Association of the KIAA0319 dyslexia susceptibility gene with reading skills in the general population". The American Journal of Psychiatry 165 (12): 1576–84. doi:10.1176/appi.ajp.2008.07121872. PMID 18829873.
- ^ Grigorenko EL, Wood FB, Meyer MS, Pauls DL (February 2000). "Chromosome 6p influences on different dyslexia-related cognitive processes: further confirmation". American Journal of Human Genetics 66 (2): 715–23. doi:10.1086/302755. PMC 1288124. PMID 10677331. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1288124.
- ^ Schumacher J, Hoffmann P, Schmäl C, Schulte-Körne G, Nöthen MM (May 2007). "Genetics of dyslexia: the evolving landscape". Journal of Medical Genetics 44 (5): 289–97. doi:10.1136/jmg.2006.046516. PMC 2597981. PMID 17307837. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2597981.
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